'''Read codes''' arewere the standard [[Medical terminology|clinical terminology]] system used in [[General Practice]] in the United Kingdom before 1 April, 2018, when they were replaced by [[SNOMED CT]]. ItThey are still permitted for use in NHS secondary care settings, such as dentistry and mental health care until 31 March, 2020. Read codes supportssupport detailed clinical encoding of multiple patient phenomena including: occupation; social circumstances; ethnicity and religion; clinical signs, symptoms and observations; laboratory tests and results; diagnoses; diagnostic, therapeutic or surgical procedures performed; and a variety of administrative items (e.g. whether a screening recall has been sent and by what communication modality, or whether an item of service fee has been claimed). It therefore includes but goes significantly beyond the expressivity of a [[diagnosis code|diagnosis coding]] system.
